Casting machine



Oct. 14, 1930. G, -WILSQN 1;778,652

CASTING MACHINE Filed May 31, 1928 lili/HMH mammoet; 14,1930

UNITED *'sx'la'l'u's.v

PATENT] omc-E Gnomz L. wILsoiLor DULUTH, nnhmso'ra This invention relates tocasting machines and has special reference to one particularly ada ted forus'e by dentists or those of similar' pro ession in making more or less delicate gold castings or the like. l'

The principal object is to`produce 'an innproved type of oentrifug'alcasting machine that will forceth'e molten metal of which the 'casting is to be made into the mold as spon- 15aneously as possiblewah the desireamouen state of the metal. i

Another object isto produce such/la ina-4 chine having simple means whereby. the desired initial thrust may be most delicately va-..

ried'to suit specific requirements.

Other objects and advantages of the in ventionwillv appear inthe further'descriptin thereof. Referring `now to the accompanying drawing, forming part of this application, and

wherein like reference characters indicate-like parts: Y

Figure 1 isa side eleva-tion of' one embodiment of my improved casting machine as applied to an electric power unit;

i Figure 2 is a side elevation opposlte to that i shown in Figure 1 of the Crucible and its carriage Figure 3 is'an lenlarged side elevation. of

f above the housing is mounted in any desired manner but fixed to the armature shaft 2 the balance wheel 3, preferably provided with an upstanding hub 4, and for conveniences hereinafter apparent I choose to provide the' same with a knurledsurface as at 5. The armature shaft is made to extend upwardly beyond the hub 4 and is externally screwthreaded as at 6. 'U pon this screw threaded portion is screw threadcdly mounted the cross-arm or beam 7, it being provided with shaped hub portion 8, surmounted Figure 4 1s a perspective view of the cruci -a frustro-conically by a. friction cap 9 and provided a suitable oil cup Y. A

-10, so that as the. beam is threaded ontothe armature shaft it may extend entirely through `'the hub ortion 8 without in any way interfering with the action of the machine or the 55 convenient lubrication thereof.

yThe cross-armor beam 7 extends equally in either direction from the hub portion and one extremity is provided withthe fixed upright en d plate 11 for. engagement with one 60 end of the mold ring v12 whenthe latter isset 1n between the horizontally reciprocable ad@` justable crucible carriage 13 :thelatter being provided with a head 14 having concentrical-l ly arranged stepped portionsl on` the face 65 thereof l r registration with the end of the mold ring common to the profession, said 4carnage bein made readily slidable upon one end of the eam 71. A

' Upon the carriage lland'backof the head "lof 1 4 is a comparatively small platform 16, the rear'portion of which is adjustable as desired vertleally by a suitable 'screw bolt 17, and the ent1re .carriage being readily sl'idable to any desired point on the arm by means of the set ,75-

screw 18, impingeableagainst the loweredge of the arm 7. Upon' the oppositev end of the arm 7 is' mounted the slidable counterwei ht 19 held Vthereupon by means ofa suitable th 20-and adjustable longitudinally of the arm so as-to counterbalance the crucible carriageV ingI` being obvious. L

`'and mold upon the opposite end; itsfunotiono one side of the motorlhousing 1 I-have-S `fixed a bracket 21 which supportsvupon the e 4horontal 'platform 22 thereof Vthe Aautomatic cutout switch, comprising the block 23 which is bifurcated in its uppermost right ,hand corner as' viewed in Figure 3 of the draw-f90 mg', and in which cutout portion is pivotallymounted as at 24 thelev'er 25; it bein squared l in its lowermost end as at 26 and hel between the two spaced insulated plates 27, they snug- .1yfilling the cutout portion lof the' block, and 05. a unitary ortion thereof/ extending ,above the block'. pon this uppermost extension of the insulatingblock is mounted theconductor bridle 28 which surrounds saidextension upon two sides and'terminates forwardly'therecf 1 indicated at 32 being connected to the bridle i as at 33, while the other terminal 34 of the motor operating circuit is connected as at 35 to the half bridle 36 which is attached to the unitary portion of the insulating material below the bridle 28 and spaced therefrom as well as spaced from the block 23. This half bridle terminates vat its forward end in an L-shaped downward extension 37 bent outwardly away from the block, normally with its free end in contact with the shaft 24 forming the pivotal connection of the lever 25, so that when this lever is in its upright position or in any way engaged by the bridle v 28 the motor circuit is complete in respect to the cutout switch.

The upper portion of the lever 25 is somewhat enlar ed as at 38 and insulated, it extending su ciently far to at all times when so in u right osition be in the path of the arm 7. hus wA en suicient power is applied to the cross arm in `its attempt to follow the rotation' of the armature shaft and force the lever to an inclined position as shown in dotted lines, Figure 3, it will still maintain its contact with the free ends 29 of the bridle 28 until such time as it passes the abrupt angle formed by the diverging ends thereof when their inward spring action will further expel '40 the lever, thereby opening the circuit; it being understood that this is a bypass circuit in the main motor.` operating circuit which latter is controlled by a su'itable momentary switch such as indicated at 39. i

The crucible 40 is of the common type, ex-

cept that one side thereof indicated at 41is brought upto an abnormal extent over the basin therein and the latter is formed slightly to one side of the axis of the discharge 5o opening of the crucible, said inclination being in the direction of the travel of the supporting arm so that the initial movement of the arm would have a more direct thrust to' wards the discharge o ning into the mold 155v and whereby any possi le splashing or spill'- ing of the molten metal is overcome.

As before stated the normal tendency of the arm 25 when placed upright is to there rel' main, and this tendency is suicient to hold 60 the cross arm l(the counterweighted end of which is supposed to engage same just prior to making a casting) against movement with the initial'rotation of the armature 6. As the motion of the latter continuesffresulting in fighe screwing down of the .cross arm thereupon until the lower face of the hub 8 engages the face of the hub 4 of the balance wheel, or rather the cushion washer 42 thereupon, the cross-arm will instantly follow at the attained speed of the motor and ower to the motor will continue so long ast e lever 25 is in engagement with the extensions of the bridle 28; this being purposely designed so that such power may continue for the fraction of a second to hold the motor at such attained speed, and carry with it the armature and its load. However it will be understood that the rotative action of the arm 7 will instantl force the arm 25 to an inclined position as t e arm 7 passes over the free end 80 of same, and thus break the electric circuit to the motor though somewhat gradually as previously described by the drag of the arm 25 through the inclined portions of -the bridle.

From the foregoing it is apparent that the motor after being started by pushin the impulse switch 39 will attain full spec prior to the screwinfr down of the arm 7 to the balance wheel 5 and which latter rovides the neces- 90 sary augmented force to instantly grab said crucible carrying arm and rotate it immediately at the attained speed of the motor, thus providing the all essential centrifugal thrust to the molten metal in forcing it into the more minute intricacies of the mold in which the casting is formed.

The use of this machine has further demonstrated the fact that but a fraction more than the actual amount of material for forming the casting is ample, whereas with the common centrifugal casting machine a much larger surplus of material is necessary, -inlvariably forming what is known as a button at the entrance of the gate to the mold, Aand as is known to those versed in the art repeated melting of metalsuch as gold or the like is detrimental.

It is to be understood that modifications of the embodiment here illustrated may be resorted to, and that the invention may be employed in a machine driven by other power than electricity. v

Having thus -described my invention, what I claim and desire to secure by Letters Patent, is:

l. A dental casting'machine comprising a power unit, means operated by the initlal movement ofthe power unit, mold and crucible carrying means upon said last mentioned means, and means whereby the mold and crucible meanss operated by and subsequent to the initial action of thepower unit.

2. A dental casting machine compris' a. power unit', centrifugal mold and crliclsxile 125 carrying means oerable by the power unit, and means Awhere ythe mold and crucible means is operated subsequent tothe initial action of the owerunit.

3. A dents, Vcasting machine comprising a 1z0 power unit, centrifugal mold and crucible carrying means operable by the power unit, means for starting the power unit, and means whereby when the power unit attains suiiicient speed it will operate said first mentioned means immediately at the attained speed of the power unit.

4. A machine of the type described comprising an upright shaft the upper extremity lo of which is screw threaded, means for rotating said shaft, a cross arm mounted upon said shaft, crucible and mold carrying means `upon one end of the'cross arm and an adjustable counterbalance upon the other end', and automatic means whereby initial rotation of the shaft is accomplished for a predetermined time prior to aiecting the cross arm and substantially simultaneously stopping the shaft. 5. A casting machine of the class described including a motor, a manually operable starting switch therefor, counterbalanced crucible and mold supporting means mounted upon the armature of the motor and operable thereby, and an automatically operated switch operable by the action of the crucible and mold supporting means.

6. A casting machine of the class described including, a motor, a manually operable momentary switch for starting the motor,

`i3() crucible and mold supporting means carried by the motor armature, and a cutout switch automatically operable by the action of the crucible and mold supporting means irrespective of the action of the momentary 5 switch.

In testimony whereof I afiiX my slgnature.

GEORGE L. WILSON. 

